Add reveal-conceal password option

What does this MR do and why?

Add the option to reveal/conceal password in the password field

Screenshots or screen recordings

How to set up and validate locally

• Sign out.
• Visit /users/sign_up. Check password field
• Visit /-/trial_registrations/new. Check password field

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #90